Interrupter for ignition systems



W. W. DEAN.

INTI-IRRUPIER FOR IGNITION SYSTEMS. APPLICATION FILED OCT. 4. 1918. RENEWED MAR. 31. I920.

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W. W. DEAN. I

iNTERRUPTER FOR IGNITION SYSTEMS- APPLICATION FILED OCT. 4, 191B. RENEWED MAR. 31. 1920.

Patented Apr. 25, 1922.

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UNITED STATES PATENT OFFICE.

WILLIAM WARBEN'DEAN, or nnwanx, New JERSEY, ASSIGNOR 'ro SPLITDOBF nanorarcn. conramr, or NEWARK, NEW JERSEY, a CORPORATION or NEW JERSEY;

INTERRUPTER FOB IGNITION SYSTEMS.

Specification of Letters Patent.

Application filed October 4, 1918, Serial No. 256,839. Renewed larch 31, 1920., Serial No. 370,273.

To all whom it may concern:

Be it known that '1, WILLIAM W. DEAN,.

acitizen of the United States, residi at Newark, in the county of Essex and. tate of N ewxJ erse'y, have invented certain new .and useful Improvements in Interrupters for Ignition Systems, of which the following is a specification, reference being had to the acrupter used in connection with an ignition magneto.

In the patent granted to H. R. Van Deventer, July 18th, 1916, No. 1,191,856, there is shown and described an interrupter for ignition magnetos, wherein the contacts have .a sliding engagement with each other, as well as a. movement relative to each other for interrupting the circuit to produce the spark. One of the purposes of this sliding ,engagement of thecontacts, is to insure that the contacting surfaces shall be clean and free from deposit thereon; so that the surface resistanceto the flow of the current through the contacts when closed, is reduced to a minimum.

An object of the present invention is to embody this principle ofmaintaining clean containing surfaces in an interrupter for ignition devices, wherein the contacts are more nearly of the usual point contact type.

.The invention consists in providing de-- vicesof this character wherein the contacts while in engagement with each other, have a relative movement for cleaning the surfaces thereof and insuring a minimum surface resistance to the passing of the current when the contacts are closed and also in devices for. separating the contacts to interrupt the circuit to produce ignition sparks.

In the drawings I Figure l is a side view. of a magneto em bodying one form of the invention, the cover plate being removed from the interrupter mechanism;

Fig. 2 is an end view of the interrupter mechanism, also showing the operating cam for the interrupter; I

Fig. 3 "s a" view showing-more or less diagrammatically the two levers for controlling the contacts and the operating cam therefor. the contacts being in engagement;

Fig. 4 is a similar view and the contacts slid laterally relative to each other while Patented Apr. 25, 1922.

in engagement, for cleaning their contacting surfaces 3 Fig. 5 is a view similar'to Fig. 4,-but with' the cam omitted and showing the contacts separated 'for ignition; r

F g. 6 is a view similar to Fig. 2,-b11t showing a modified form of mechanism for moving the contacts; I

Fig. 7 is a view showing more or lessproducing the spark for diagrammatically the manner in which the contacts of the device in F ig:6 are shifted for cleaning the surfaces;

Fig. 8 is a view similar to Fig. 2, but show mg a stllLfurther modified form of the (lei-1 vices for operating the" contacts; I 1

F 9' is a side view showing the devices" asin Fig.8; Fig. 10 is an end view of thefsh'aft and the opera-ting cam of the. devices shown in- Fig. 11 is an .end view showing "stillanother form of devices for operating the con tacts; Fig. 2is a side view of the parts shown in 1-1; and

Fig. 13 is a face view of-the cam drum for operating the contacts.

The invention. is directed. broadly tov an interrupter for ignition systems wherein the current is generatedby a magneto. The interrupter includes a pair of contacts of the point-contact type and while one contact is preferably larger than the other, they are,

however, of substantially the same cross sectiona-l area. The contacts are adapted to be separated for producing the. spark'for ignition. These contacts are operated by devices which are capable of moving the contacts laterally or axially relative to each other, so asto insure that the contacting surfaces shall be cleaned and free from deposit,

thus reducing to a minimum the surface resistance to the passing of the current through the contacts. The contacts of my improved ignition system may be made of tungsten or similar material. I havei'found that tungsten may be used to form" the contacts in an ignition system of the above character, rovided the contacting surfacesof the tungsten metal are kept clean and free from. deposits and if these contacts are pressed forcibly into' engagement, so that through the increased force and the clean surface contact, the surbroad principle in an interrupter having face resistance to the current passing through the contacts is reduced to a minimum. I

In the patent to Van Deventer above referred to, an apparatus has beendescribed wherein the contacts are moved in two directions, one for rubbing the surfaces and the other for separating the contact surfaces to produce the spark. I have embodied 'this tungsten contacts and wherein the contacts are of the point-contact type. The contacts are se arated in the usual manner for producing t e spark. In'addition to this separating movement of the contacts, I have also provided devices which will cause the contacts to move laterally while in engagement oraxially while in engagement for cleaning the contacting surfaces thereof.

The invention may ssibly be better understood by reference in detail to the drawings, which show several ways of carrying out m invention. 4 v

In igures 1 to 5, inclusive, of the drawings, I have shown an arrangement wherein both contacts are bodily movable, one contact being movable in a direction for "producing-a sliding effect of one contact on the other, while the contacts are in engagement and the other contact being movable for separating said contacts toproduce the ignition spark. The magneto is indicated diagrammatically at M in the'drawings. At one endof the main shaft and attached to the magneto frame, is a support 1. This support 1 is capable of being shifted rotation ally about the center of the operating shaft. This may be accomplished by means of a projecting arm indicated at 2. Mounted on this support 1, is a lever 3. Said lever is carried by a pivot screw 4, on which it may freely swing. This lever 3 carries a contact 5 which is preferably of tungsten formed as a part of a threaded shank 6, which enables the contact to be adjusted at the end of the lever 3. A spring 7 operates upon the lever 3 and normally tends to turn the same so that the lever rests against a stop pin 8. Also mounted on the support 1 and insulated therefrom, is a block 9. This block 9 carlies a lever 10, which is mounted to turn freely about a pivot screw 11. A. spring 12 operates upon said lever 10. Said lever 10 carries a contact 13, which is adapted to co-operate with the contact 5.v This contact 13 is also preferably made of tungsten. The contact 5 is slightlylarger in diameter than the contact 13, so that said contacts may be moved laterally relative to each other, without the smaller contact passing beyond the limits of the larger contact. As distinguished from the contacts in the Van Deventer patent, these contacts 5 and 13 are of' substantially the same size and may, therefore, be said to be of the usual point-contact type.

' The spring 12 operating on the lever 10 normally tends to hold the contacts in enof the-magneto, is a cam .14. Said cam-may be secured to the shaftby a suitable screw 15. This cam has a hi h oint 16 and a high point'17. The two ig points 16 and 17 are similarly shaped and symmetrically disposed,-that is to say, these high points are diametrically op osite each other. The lever 10 is provide with a bearing block 18,"which is adapted'to run on this card 14. The lever 3 is formed with a bearing block 19, which also runs'on the same cam 14.

.These blocks 18 and 19 are not diametrically disposed relative to the axis of the shaft of the magneto, so that first'one block and then the other will be under the influence of a cam projection. When the cam is positioned as shownin Fi ures 2 and 3, neither block is under the in uence of these camprojecheldin enga ement by the spring 12, and it will be note that the contact 5 moves laterally relative to the contact 13.

As the cam projection 16 moves away from this block 19, it releases the lever 3, so it moves back again against the stop pin 8, and this brings the contacts back into normal position.- All this occurs before the lever 10 comes under the influence of the rotating cam projection. The purpose of this movement of the contacts is to clean the surfaces and prevent the accumulation of deposit thereon. I

The springs 7 and 12 are relatively heavy ones, sothat the contacts are pressed together with considerable pressure, and through this cleaning of the surfaces and increased pressure, I am able to reduce the surface resistance to the passing of the current through the contacts to a minimum. ,In Figure 5 of the drawings. I have shown the contacts separated for interrupting the current to produce the spark for ignition.

In Figures 6 and 7 of the drawings, I have shown a slightly modified form of the arrangement of the levers. In the forms shown in Figures 1 to 5 of the drawings, the lever 3 is fulcrumed intermediate its ends. In Figure 6 of the drawings, this lever is indicated at 3 and it will be noted that said lever engages the cam between its-ends. The lever 3 is held by the spring 7 ,against a stop pin 8. Mounted on this lever 3 is the contact 5. The lever 10 also engages the gagement. Mounted on the end of the shaft which the contacts are separated to produce the spark. I I

In Figures 8 to 10 inclusive, I have shown a further modified form of operating means for moving the contacts while in engagement for cleaning their contacting surfaces and for separating the contacts to produce the spark. In this form of the invention, the contact which has no movement for interrupting the circuit, is rotated about its axis, for the purpose of cleaning the contacts when they are in engagement. Mount-' ed on the end of the magneto shaft is a cam drum 20, which has a face cam 21. This cam drum also'carries a support 22, in which the ignition point 23 is mounted. These parts are so constructed that the ignition point or contact 23 rotates with the main shaft of the magneto, Co-operating' with this contact is the movable contact 24,-which is moved toward and from the contact 23, fo making and breaking the circuit. This movable contact is carried by an arm 25 which other.

is pivoted at 26. Said arm is connected to a sleeve 27, which turns on the pivot pin 26. Located within the sleeve is a suitable spring which normally forces the contact 24 into engagement with the contact 23. The pivot pin 26 is carried by a bracket 28, which is mounted on a block 29 insulated from the supporting base 1. A brush 30 is carried by the base 1 and this brush is forced by a spring 31 against the outer face of the'drum cam 20. This serves as a suitable ground for the contact 22. As the main shaft rotates, the contact 23 will rotate and if the contact 24 is in engagement therewith, the contacting surfaces will be kept clean through this rotation of one surface on the .The lever or arm 25 carrying the contact 24. also carries a block 32 which bears against the face cam 21 and this drum-is so shaped as to permit the contacts to come together to establish a circuit therethrough then separate the contacts to interrupt the circuit to produce the spark.

In Figures 11 to 13 inclusive, I have shown a still further modified form of the invention. In this form of the invention, the contact which is stationary so far, as the separating of the contacts to form, the spark is concerned, is rotated about its axis to ac complish the results stated in connection with the description of the shafts shown in Figures 8 to 10 inclusive. The rotation of the stationary contact however, is accomplished in a different manner. In this form of the invention, the stationary contact is indicated at 33. This contact is carried by a short shaft 34 mounted to rotate in suitable bearings 35. The movable contact is indicated at 36 and this is carried by alever 37 having a block 38 which is adapted to run on a cam 39 formed in the surface of the cam. drum 40. This cam 39 is shaped so as to separate the contacts at proper inter vals and the contacts are held closed by a spring 41. The shortshaft 34 is provided with a toothed wheel 42. Mounted on the cam drum 40 is a spiral thread 43 which engages this toothed Wheel and rotates the shaft 34, carrying the contact 33. The supporting'bearings 35 are carried bya bracket 44 which'is insulated from the support 1, This support 1 as above noted, is capable of being shifted for varying the time of interrupting the circuit for advancing or retarding the spark.

From the above, it Will be apparent that I have provided'an interrupter mechanism for ignition systems which is especially adapted to an interrupter of, the pointcontact type, that is, wherein the contacts are substantially the same in cross sectional area and which enables the contacts to be made of tungsten or similar material and at the same time an eflicient spark.may be created. The essential features of the invention which permit this to be accomplished, are the movement of one contact on the other while they are closed in order to clean the surfaces andprevent the accumulation of deposit thereon and the pressing of the contacts forcibly together so as to reduce to a minimum the surface resistance between the engaging portions of the contacts and thus insuring a maximum current flow. It is obvious that many changes may be made in the details of construction and other forms devised for accomplishing the functions described above, without departing from the spirit ofthe invention as set forth in the appended claims.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is

1. In a magneto ignition mechanism, the combination of cooperating contacts of substantially the same area, a rotating cam projectlon, devices for supporting said contacts. sald devices being disposed so as to be engaged in succession by said cam projection, and whereby when oneof said devices is operated, the contacts will be moved away from each other for producing ignition spark and whereby when the other device is moved, the contacts while in engagement will be moved laterally for freeing the contacting surfaces of deposit.

2'. In a magneto ignition mechanism, the combination of cooperating contacts of substantially thesamearea, a rotating cam projection, devices for supporting said contacts, said, devices being disposed so as to be engaged in succession by said cam projection,

and whereby when one of said devices is operated, the contacts will be moved away the other and whereby the other contact may be moved laterally of the first named contact and mechanism for operating the same, saidmechanism including a cam projection operating first to move the contacts relative to each other and then to separate the contacts. v I

i 4. In a magneto ignition mechanism, the combination of co-operating contacts, a pivoted lever. for each contact, a spring associated with each lever and. a cam pro ection operating upon said levers in succession, said levers being shaped and disposed so'that the movement ofone lever causes the contacts to slide laterally on each other while in en agement and the movement'of the other ever causes the contacts to be moved away from each other and separated 5. In a magneto ignition mechanism, the combination of co-operating contacts, a pivoted lever for each contact, a spring associated with each lever and a cam projection operating upon said levers in succession, said levers being shaped and disposed so that the f movement of one lever causes the contacts to slide laterally on'each other while in engagement and the movement of the other lever causes the contacts to be moved away.

from each other and separated and 'means H for supporting the levers whereby they may be shifted for timing purposes.

g 6. In a magneto ignition mechanism, the combination of co-operating contacts, a pivoted lever for each contact, a shiftable member on which said levers are pivoted, one of said levers being insulated from said member, a rotating cam having oppositely disposed camprojections, blocks carried by the respective levers and adapted to engage said lever causes the contacts to be moved away from each other and-separated. 7. In a magneto ignition mechanism, the

combination of co-operating tungsten contacts of'substantially the same area, a pivoted lever for each contact, a spring associated with each lever, a cam havlng oppositely. disposed projections for. 0 rating said levers, each lever having a bloc adapted to engage the cam projections, said blocks being disposed so that the levers are op erated in succession, said levers being shaped so that the contacts are caused to slide laterally on each other when one lever is moved and are caused to separate when the, other lever is moved, said springs operating to forcibly press the contacts into engagement. 8. In a magneto ignition mechanism, the combination of cooperatin'g tungsten contacts of. substantially the same area, va .pivoted lever for each contact, a spring associated with each lever, a cam having oppositely disposed projections for 0 rating said levers, each lever having a bloc adapted to engage the. cam projections, said blocks being disposed so that the levers are operated insuccession, said levers being dis sed so that the contacts are caused, to slide aterally on each other when one lever is moved and are caused to separate when the other leveris moved, said springs operating to forcibly press the contacts into engagement, and

means for supporting said levers whereby they may shift about the cam for timing purposes.

9. In a magneto ignition system, the combination of co-operating contacts, a lever for each contact, a cam havin a'projection'for operating said levers, eac lever having a block adapted to engage the cam projection,

said blocks being disposed towardone side of a diameter passing through the axis of the cam so that the levers are operated in succession, said levers being so shaped that the contacts are caused to slide on each other 'when one lever is moved and are caused to y be separated when the other lever is moved.

In testimony whereof I hereunto aflix my signature.

WILLIAM WARREN DEAN. 

